THE BARNACLES IN THE U. S. NATIONAL MUSEUM. 6 



Family LEPADID^^ Darwin. 



Cirripedia having a peduncle, flexible and provided with muscles. 

 Scuta furnished only with an adductor muscle; other valves, when 

 present, not united into an immovable ring (Darwin). 



Professor Gruvel has proposed to dismember the family Lepadidas, 

 recognizing four families, nearly corresponding with the groups 

 herein recognized as subfamilies, thus: 



Polyaspidte Gruvel = Scalpellina3. 



Pentaspidte Gruvel = Lepadina? -\- Concliod&nna and Oxynaspis. 



Tetraspidte Gruvel = Iblini;e. 



Anaspidse Gruvel = Alepadina^— Concliodertna. 



I would probabl}^ have accepted GruveFs families had the names 

 been based upon generic terms; yet in that case I would be disposed to 

 place Oxynaspis with Scalpellum rather than with Lepas^ and on 

 account of the structure of the scutum I would group Conchoderma 

 with Alipas, though the armature of the cirri is different, and may 

 indicate a closer relation to the pentaspidian group. 



The terminology of the external parts of pedunculate barnacles is 

 sufficiently explained by the following diagrams: 



.■1 



B 



Fig. 1.—Latep,al views of (.-1) Mitella, {B) Scalpellum, and (C) Lepas. c, carina; cl, carinal 



LATUS; il, INFRAMEDIAN LATUS; I, LATERA; J), PEDUNCLE: r, ROSTRUM; H, ROSTRAL LATUS; S, SCU- 

 TUM; sc, subcarina; t, tergum, ul, upper latus. 



KEY TO THE GENERA OF LEPADID.E.« 



a. Umbones of scuta and carina above the middle of the plates or api(;al; a basal 

 whorl of plates below the principal five; peduncle scaly. 



Subfamily Scalpellinje. 

 h. Valves 18 or more, all with apical umbones; latera in the basal whorl numerous. 



Genus Mitella. 

 bl>. Valves 12 to 15, the basal whorl of plates with 2 or H pairs of latera. 



Genus Scalpellum. 



oWith the exception oi Jbla, all the genera included in this key occur in North 

 American waters. Only such genera as are treated of in the following pages are 

 included in the key. 



